Black Holes - Professor Joseph Silk

Supermassive black holes lurk in the very centres of galaxies. The Milky Way has a central black hole of four million solar masses. Today it is quiescent. But we have reason to believe that millions of years ago it was active. http://www.gresham.ac.uk/lectures-and-events/black-holes

Traces of exploded debris are seen around our galactic centre that arose in a violent explosion some tens of millions of years ago. Most galaxies have massive central black holes, in some cases weighing billions of solar masses. These once were the sites of the most energetic phenomena in the universe, that astronomers recognise as quasars. I will describe feeding the monster within: the rise of the quasars, and how supermassive black holes formed long ago. These immensely luminous objects in the nuclei of galaxies were active when the universe was young. Current data suggests that supermassive black holes formed along with the first galaxies. The ultimate window on building massive black holes is gravity waves, and I will describe gravity wave experiments being planned to search for traces of the formation of such black holes.

The transcript and downloadable versions of the lecture are available from the Gresham College website: http://www.gresham.ac.uk/lectures-and-events/black-holes

Gresham College has been giving free public lectures since 1597. This tradition continues today with all of our five or so public lectures a week being made available for free download from our website. There are currently over 1,900 lectures free to access or download from the website.